Compositionally graded aluminum-silicon alloy fabricated via friction extrusion. (December 2022)

• Record Type: Journal Article
• Authors: Wang, Tianhao; Li, Xiao; Gwalani, Bharat; Grant, Glenn J.; Powell, Cynthia A.
• Is Part Of: Materials today communications. Volume 33(2022)
• Publication Date: 2022-12
• Subjects: Al-Si alloy -- Gradient -- Solid phase fabrication; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2022.104423
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: A novel solid-phase gradient alloying technique was developed for a high throughput composition-microstructure-mechanical property assessment. Friction extrusion of a two-piece billet setup facilitated the formation of a seamless compositionally graded aluminum (Al)-silicon (Si) extrudate rod, with Si concentration in Al matrix gradually increasing from ∼1 at% at one end to ∼7 at% at the other end of the rod. We observed a strong dependence of the Al grain size, morphology, and texture on the Si concentration. The Si particles pinned the recrystallized grain boundaries resulting in refined (< 10 µm) and textured grains in the high Si content region, while the Al grains in the low Si region are equiaxed, randomly textured, and with a larger average size (∼50 µm). The hardness of Al-Si gradient extrudate increases by ∼50% percent with a 6 at% increase in Si content due to Hall Petch and particle strengthening effects. Our approach demonstrates the use of a solid phase processing technique to successfully produce a defect-free continuously compositionally graded bulk components thus overcoming the limitations of porosity and material heterogeneities commonly observed in other techniques such as by additive laser deposition. Graphical Abstract: ga1 Highlights: A novel solid-phase gradient alloying technique is developed. Current method provides a microstructure applicable to structural applications. Effect of Si content on microstructure and performance of Al-Si alloy is displayed.